The yellow rust outbreak on the wheat crop in Argentina this year is the largest since 1930, stated disease expert agronomist Marcelo Carmona. According to Trigo & Farinhas consultancy, the attacks on the crop were first reported in September by the Buenos Aires Cereal Exchange.

In the middle of September, the Córdoba Cereal Exchange reported that most of the province had been affected, while the province of Entre Rios declared a red alert against the disease. Reports from the National Agricultural Technology Institute (INTA) showed it had detected cases of re-incidence of the same disease despite applications of fungicides.

Carmona stressed that the fungus produced by yellow rust was a high migratory capacity pathogen with strong genetic variability and high adaptation to more elevated temperatures. One of the characteristics that differentiates it from the others is that it attacks earlier than other types of rust and is the most important wheat disease in the world, because once it attacks, it can dry the plant, something that does not happen with other types of rust, he revealed.

Trigo & Farinhas noted, “Decisions must be made without taking into account the plant's phenological states. Lower infected leaves continue to infect the upper leaves very aggressively as one pustule produces nearly 3,000 spores a day.”

The consultancy asked agronomist Carlos Hugo Godinho about the effects of yellow rust on wheat and was informed that it was something that did not occur frequently in Brazil, but what is known is that it affects the productivity rather than the quality.

Such information should be taken cautiously, because depending on the degree of attack and the applications done, the effects are not extensive. “What increases, without any doubt, is the final cost to the producer, as it happens on soybean,” concluded Godinho.